This is from our Microsoft TAM:
After looking into this I found some very interesting news about this topic.
As you and I discussed, in Outlook 2003 there were encryption settings for
- No Encryption
- Compressible Encryption (default)
- High Encryption
The information I located stated that this caused a lot of confusion in 2003
and that the High Encryption setting was not as strong as the terminology
implied. Because of confusion and the fact that encryption is also available
at the file system level, this setting was removed in Outlook 2007. The
current recommendation in Outlook 2007 is that if you wish for the .ost to be
encrypted is to use the Encrypted File System (EFS) or in later versions of
the operating system you can also use Bit-Locker Encryption.
